expo middleware with clerk auth

+middleware.ts

import { type ImmutableRequest } from 'expo-server';

import { createClerkClient } from '@clerk/backend';
import type { MiddlewareFunction } from 'expo-router/server';

const clerkClient = createClerkClient({
    secretKey: process.env.CLERK_SECRET_KEY,
    publishableKey: process.env.CLERK_PUBLISHABLE_KEY,
});

// https://docs.expo.dev/router/reference/middleware/#configure-middleware-matchers-optional
export const unstable_settings = {
    matcher: {
        // Only run on API routes and specific paths
        patterns: ['/api/[...path]'],
    },
};

// You can only have one root-level +middleware.ts in your app.
const middleware: MiddlewareFunction = async (request) => {
    const patchedRequest = patchRequestForClerk(request);

    const { isAuthenticated } = await clerkClient.authenticateRequest(patchedRequest);

    if (!isAuthenticated) {
        new Response('Unauthorized', { status: 401 });
    }
};

export default middleware;

/**
 * Patches request to avoid duplex issues with unidici
 * For more information, see:
 * https://github.com/nodejs/node/issues/46221
 * https://github.com/whatwg/fetch/pull/1457
 *
 * source: https://github.com/clerk/javascript/blob/main/packages/tanstack-react-start/src/server/utils/index.ts#L61
 */
export const patchRequestForClerk = (request: ImmutableRequest) => {
    const clonedRequest = new Request(request.url, {
        headers: request.headers,
        method: request.method,
        redirect: request.redirect,
        cache: request.cache,
        signal: request.signal,
    });

    // If duplex is not set, set it to 'half' to avoid duplex issues with unidici
    if (
        clonedRequest.method !== 'GET' &&
        clonedRequest.body !== null &&
        !('duplex' in clonedRequest)
    ) {
        (clonedRequest as unknown as { duplex: 'half' }).duplex = 'half';
    }

    return clonedRequest;
};